Thrombectomy catheters usually comprise a catheter tube. The tube is commonly called a "shaft" and the passage inside the tube is commonly called the "lumen". A thrombectomy catheter usually has at its distal end a coiled spring which is secured in and projects forwards of the distal end of the shaft. This spring is enclosed in an inflatable balloon which is secured to the shaft near its distal end. Thus, the spring and the balloon form a flexible tip of the catheter. When the catheter is in use, the balloon can be inflated by the pressure of fluid transmitted to the interior of the balloon through the lumen.
An object of the present invention is to provide a thrombectomy catheter or similar tubular surgical instrument with an improved tip. Another object is to provide a thrombectomy catheter with which the inflatable balloon is secured to the shaft with greater security than is provided in existing such catheters.